Electronic images can be stored in a number of different formats. The most common formats for storing images today are the Joint Photographic Experts Group (“JPEG”) standard or bit-maps. Bit-maps include a set of data (one-bit for monochrome to multiple bytes for true color) for each pixel (or dot) of an image. A bit-map image in XGA format (1024×768 pixels) using 64 k colors (two bytes) would require nearly 1.6 million bytes of storage. JPEGs use compression techniques to reduce the storage needed with minimal loss of detail. Typically JPEGs reduce the storage necessary by a ratio of 10:1 or 20:1 (greater compression can be achieved with further losses of detail).
Ink-jet printers have large numbers of ink-jets which deposit drops of ink on a medium. The drops are very small and different colored drops can be combined to achieve true color printing. A typical print head can have 300 to 600 ink-jets. For ink-jet printers, a print swath is data that indicates when each ink-jet is to deposit a drop of ink on the medium for a single pass of the print head over the media. Host-based printers rely on the host (typically a computer) to provide the printer with print swaths for each pass of the print head over the media. Host-based printers typically require a connection between the host and the printer to transfer the print swaths to the printer.
Other types of printers may have the ability to access different format data images (e.g., JPEG) and convert the data into the required print swaths. A digital photo printer would be an example of this type of printer. A digital camera takes a picture and stores the image on a memory card in JPEG format. The memory card can be removed from the camera and inserted into a digital photo printer. The printer can read the JPEG image on the memory card and convert the JPEG image to print swaths and print the image. This type of printer requires significant processing power in order to convert the stored image into the print swaths required for printing.